Keyboard functioning in every mode but normal

Try using a wired USB keyboard.

With some laptops I have seen the keyboard act this way.....or sometimes the other way where it won't work before logging into macOS, but works fine within macOS after login. Could be an issue with the built-in keyboard or the Logic Board, but there is no way to be certain which one without swapping parts.

If this is an Intel Mac, then you can try an SMC Reset and a PRAM Reset (hold the PRAM Reset for at least two chimes if possible...three on the older Magsafe models). You must use the built-in keyboard for the SMC Reset, but an external wired USB keyboard can be used for the PRAM Reset.

You can also try running the Apple Diagnostics to see if any hardware issues are detected. The only useful diagnostic is one which produces an error.

I highly recommend you perform a clean install of macOS in order to ensure the OS is clean & fully functional and that the previous owner did not leave something nasty behind. This should always be done whenever acquiring a used device. Here is an Apple article showing what the previous owner should have done before selling the Mac:

What to do before you sell, give away, or trade in your Mac - Apple Support

A clean install is when the drive is erased, followed by reinstalling the OS, so make sure to back up all your data first. I recommend creating a bootable macOS USB installer so you have more options in case something goes wrong.

Create a bootable installer for macOS - Apple Support

FYI, it is always best to provide the exact model of the Mac and version of macOS being used since different hardware & software can have their own issues & quirks, plus we may be able to provide a more specific answer instead of generalizations. You can get this information by clicking the Apple menu and selecting "About This Mac".

It appears this is a Mid or Late 2007 model MBPro 15" or 17" and all of these models appears to have shipped from the factory with OSX 10.4.9.

Is the secondary account an admin user account or just a Standard account?

Just noticed the steps you listed in the first post are not quite correct (you really should run a file system integrity check before mounting it as writable...it is the first command "fsck -fy /"):

fsck -fy  /
mount  -uw  /
rm  -i  /var/db/.AppleSetupDone
reboot

This assumes that this was how Apple did things with macOS 10.4. You neglected to type the "r" in the post here and the " -i " is just a good idea to allow you to confirm the file being deleted.

This laptop should be able to run macOS 10.11 El Capitan, but the fact that it appears this laptop was never upgraded to later versions of macOS makes this difficult. You would first need to install OSX 10.6 Snow Leopard, before you could run the macOS 10.11 installer. You would need to purchase the retail upgrade OSX 10.6 Snow Leopard DVD from someone online.

If you have the original OSX restoration CD/DVD from the factory or an OSX 10.6 upgrade DVD, then you could use it to reset the password for the main admin account, but I would just perform a clean install of macOS.

Use the "fsck" command without the trailing slash "/" character. If you look right above the command prompt you will see it actually has the "fsck" & "mount" commands you should use listed there. I was just going from memory and did not realize "/" was not necessary.

FYI, you can rotate the photos on your iPhone/iPad by editing the photo and rotating couter-clockwise, then saving the changes. This way you will have properly oriented photos when posting here. I'm sure there is a similar mechanism if using an Android device.

Since this was gifted and you are unable to create the new admin user account during the setup process, then it would be best to perform a clean install of macOS using by purchasing an OSX 10.6 Snow Leopard upgrade DVD since this Mac may never have had a later OS installed (in that case you may need to first install macOS 10.7, then 10.11, but you could try 10.11 USB installer if you have access to another compatible Mac).

There is a good chance the internal hard drive is failing, or there may be some other hardware failure.